1. Field of the Invention
The present invention relates to a method and apparatus for encoding and decoding an audio signal, such as a voice signal or a music signal, and more particularly, to a method and apparatus for encoding and decoding a signal corresponding to a high frequency band in an audio signal.
2. Description of the Related Art
In general, a signal corresponding to a high frequency band is less important than a signal corresponding to a low frequency band in terms of a human being's perception of an audio signal as a sound. Thus, when an audio signal is encoded, if coding efficiency must be increased due to a limitation in the number of available bits, a signal corresponding to the low frequency band is encoded by allocating many bits thereto, while a signal corresponding to the high frequency band is encoded by allocating less bits thereto.
However, in some cases, the signal corresponding to the high frequency band may be important and the human being should be able to perceive an audio signal as a sound. In this case, by not exactly encoding the signal corresponding to the high frequency band, sound quality of a signal decoded by a decoder may be degraded.